Cistern Size Calculator
Calculate water storage needs for your household
Inputs
Average: 50 gal. Conservation: 20-30 gal.
How many days without resupply
Daily usage guidelines
Storage recommendations
Container sizes
How to use this calculator
- 1Enter the number of people in your household
- 2Estimate daily water usage per person
- 3Decide how many days of water you want to store
- 4Choose whether to add a safety buffer
Water storage guidelines
FEMA recommends storing at least 1 gallon per person per day for drinking and sanitation. For extended emergencies, plan for 3-14 days minimum.
Conservation mode (20-30 gallons/person/day) covers drinking, cooking, and minimal hygiene. Normal usage is 50-100 gallons including bathing and laundry.
Consider your situation: Hot climates need more water. Activities like gardening or livestock significantly increase needs. Always add a buffer for unexpected use.
Frequently asked questions
How much water does a person need per day?
FEMA recommends 1 gallon per person per day for drinking and sanitation. For full living (cooking, cleaning, bathing), plan for 20-50 gallons in conservation mode, or 50-100 gallons for normal usage.
How long does stored water last?
Properly stored water can last 6 months to indefinitely. Use food-grade containers, store in a cool dark place, and consider adding water preserver or rotating stock every 6-12 months.
What size containers should I use?
WaterBricks (3.5 gal) are stackable and portable. 55-gallon drums are economical for large storage. IBC totes (275-330 gal) are ideal for big cisterns. Mix sizes for flexibility.
Result
3,360gallons
Recommended capacity